Telephone system



C. L. GOODRUM.

TELEPHONE SYSTEM.

APPLICATION FILED MN.30.1917.

Patented Apr. 11, 1922.

Z'SHEETS-SHEET I.

C. L. GOODRUlVl.

TELEPHONE SYSTEM.-

APPLICATION FILED muse, 1911.

lflimfiwc 4 PatentedApr. 11; 1922.

2 SHEETS- SHEET 2- Char/es L Good/um.

fly I S N QFFHQE,

CHARLES L. GOODRUIRZ, O1 BROOKLYN, NEW YORK, AS IGNOR T0 WESTERN ELECTRIC COMPANY, ZNCORPURATEID, 0E NEVJ YORK, N. Y A CORPORATION OF NEW YORK.

TELLl-EIONE SYSTEM.

Specification of Letters Patent.

Patented Apr; til, 11922.

Application filed January 30, 1917. Serial No. 145,357.

To all whom it may cancer-'21 Be it known that l, Lns L. GooDRUM, a citizen of the United States, residing at o the county of ings and State o new so .iai'e invented certain new-and useful lmpro ments in Telephone Systems, of which the following is a full, clear, con-- cise, and exact description.

This invention relates to telephone systems of that type employing machine switchlng.

The present arrangement has forits purpose the production of a telephone system which will be simple in construction, economical to manufacture, and effective in operation.

In step-by-step automatic telephone systems of the type generally employed, it is customary to use combinations of fast and slow relays to control the setting and releasing of the automatic switches utilized in establishing a connection. It is the purpose of this invention to eliminate these combinations of fast and slow relays.

The main feature of this invention is the provision of circuit arrangement in which the combination of fast and slow relays is dispensed with, and in which the operations normally controlled by these relays are controlled by the magnets employed in setting and releasing the automatic ,witches.

Other features of he invention will appear from the detail description and the claims.

Referring to the drawings. Figs. 1 and 2 represent diagrammatically a portion of a telephone system employing the present invention. 1 illustrates a non-numerical switch and a first selector with the operatin circuits of said switches. Fig. 2 illustrates a connector switch and its operating circuits.

it is believed that the operation of this stem will best be understood by tr ring acell through the various link circuits and j-. nnecting switches.

When the subscriber, whose substation apparatus is indicated at A, removes his re ceiver from the switchhook, the line relay 7 t attracts its armature. This completes circuit which may be traced from grounded battery, lefthand winding of relay 74. outer armature and back contact of cut-off relay 75,, armature and front contact of line relay 74:; spring contact 7 6, left-hand armature and bacli contact of relay 77, relay 7 8 to ground.

The relay 78 is energized and attracts its armatures. At its left-hand armature it completes a locking circuit which may be traced from ground, winding of relay 78, left-hand armature and front contact of relay 78, conductor 79, to grounded battery over the circuit previously described. At the right-hand armature of relay 78, ground is applied to segment 16 of the commutator 15 to stop the finder switch in one of its operations. This circuit may be traced from ground, right-hand armature and front contact of relay 78, conductor 5, to segment 16. At the right-hand armature and front contact of relay 78 a circuit is also completed to energize the relay 80. This circuit may be traced from grounded battery, relay 80, left-hand armature and front contact of relay 78, to ground. The attraction of the left-hand armature of relay 8O closes a break point in one of the operating circuits of the finder switch. This circuit may be traced from ground, right-hand armature and front contact of relay 78, left-hand armature and front contact of relay 80, to lead 6. At the right-hand armature of relay 80, the energizing circuit of relay 77, which controls the starter wire in the well-known manner, is completed. This circuit may be traced from grounded battery, winding of relay 77, right-hand armature and front contact of relay 80, to ground.

As soon as ground is connected to lead 6, an operating circuit is completed for the rimary magnet 7 which may be traced from grounded battery, primary magnet 7, the armature of this magnet, side-switch wiper 8 in its first position, lead 6, left-hand armature and front contact of relay 80, righthand armature and front contact of relay 78 to ground. An operating circuit in parallel with the last described circuit extends from grounded battery, primary magnet 7, escape magnet 12, side-switch wiper 13 in its first position, brush 14 of the commutator 15. The primary magnet 7, by interrupting its operating circuit, moves the brushes 9, 10 and 11 of the finder and commutator brush ll until the brush 14L encounters the grounded segment 16 of the commutator, whereupon the escape magnet is energized and moves the side-switch wipers into position 2 in the well-known manner.

This prepares an operating circuit for the secondary magnet SM, which circuit may be traced from grounded battery, secondary magnet SM, armature and back contact of this magnet, side-switch wiper 8 in its second position, lead 6 to ground. The second ary magnet SM continues to operate the brushes of the finder by interrupting its own circuit until the cut-off relay 7 5 of the calling line is energized over test brush 11, side-switch wiper 18 in'its second position, to ground.

The release magnet 19 herein employed is provided with an armature which carries holding dogs to hold the brush shaft in the position to which it has been advanced, as clearly shown'in the co-pendin application of Messrs. (1L. Goodrum and Kropp, Serial No. 151,226 filed l ebruary27, 1917. Simultaneously with the energization of primary magnet 7, the release magnet 19 is energized over a circuit which may be traced. from grounded battery, release magnet19, conductor 20, normally closed con? tact 21, side-switch wiper 22 in its first position, lead 6 to ground. The release magnet 19 attracts its armature-andv thereby establishes a locking circuit which extends from grounded battery, magnet 19, its armature and front contact, side-switch wiper 22 in its first position, lead 6 to ground.

hen the cut-off relay of the calling line is actuated, the energizing circuit of escape magnet 12 is interrupted by reason of the removal of ground potential from conductors 5 and6. Escape magnet 12 thereupon deenergizes and moves the side-switch wipers into their third position.

In thethird position of side-switch wiper 22, an energizing circuit of release magnet 19 completed which extends from grounded battery, primary winding of release magnet 19, its armature and front contact, side-switch wiper 22, secondary Winding of release magnet .19, conductor 23, armature and backcontact of escape magnet 12 to ground. When the side-switchwipers 24 and 24 are moved into their third position,

the calling lineis extended to the first selector.

The primary magnet 25 of this first se lector whichmagnet also performs the functions usually performed by the welLknown line relay is energized. over a circuit which may be traced from grounded battery, lefthand winding of primary magnet 25, sidesw-itch wiper 26 in itsfirst position, lower sideofthe line, side-switch wiper 2 t in its third position, finder brush 10, substation apparatus A, finder brush 9, side-switch wiper 2 1?, upper side of the line, side-switch wiper 27, right-hand winding of primary magnet 25 toground. Primary magnet 25 in energizing attracts its armature. This c0m-- pletes an energizing circuit for the release magnet 28 which in this system operates also a as the slow-releasing relay formerly used in ductor 31, armature and front contact of primary magnet 25 to ground. Release mag=.

net 28 is energized and attracts its armatures. At its left-hand armature, it establishes a holding circuit for itself which extends from grounded battery,' release magnet 28, its left-hand armature and front contact over the circuit previously described. 2 At its right-hand armature and front contact, re lease magnet 28 closes a break point in the energizing circuit of the secondary magnet 32, which magnet in the present system operates to perform the functions normally performed by the second slow-releasing relay of systems now in use. When the sending device at substation A is operated to send impulses corresponding to the first digit of the desired number, the armature of primary magnet 25 vibrates to advance the switch and at its back contact completes an energizing circuit for the secondary magnet 32, which circuit may be traced from ground,

armature and back contact of primary magnet 25, conductor 33, right-hand armature and front contact of release magnet 28, secondary magnet 32 to grounded battery. Secondary magnet 32 attracts its armatures and at its right-hand armature and front contact completes an operating circuit for the escape magnet 34:, which circuit may be traced from ground, front contact and righthand armature of secondary magnet 32, sideswitch wiper 35 in its first position, escape magnet 34 to grounded battery.

i'it the termination of the first series of impulses, primary magnet 25 maintains its armature attracted for a relatively long interval, and at the back contactand arma ture interrupts the energizing circuit of slow-releasing secondary magnet 32. The secondaryv magnet retracts its armatures and at its right armature and front contact interrupts the operating circuit of escape magnet 34. In this instance, escape magnet 3a operates on its deenergization to move the side-switch wipers into their; second position. An operating circuit for the escape. magnet isnow completed to test brush, 36 over the following path: grounded battery, escape magnet 34, side-switch wiper 35 in its second position, conductor 37, test brush 36. In the seconc. position of side-switch wiper 38, a self-interrupted operating circuit for secondary magnet 32 is completed from grounded battery, magnet 32, armature andback contact of this magnet, sideswitch wiper 38 in its second position, armature and back contact of escape. magnet 34 to ground. The secondary magnet 32 continues to move the brushes 39, 4:0, and test brush 36 over the group of trunks until an idle trunk is located. The idle'condition of the trunk will be indicated by ground potential on the test terminal 41 of the idle trunk. ll hen test brush 36 of the selector engages this grounded test terminal, the escape magnet 34 is energized and in this instance, upon its energization, moves the sideswitch wipers into their third'position. It should here be noted that the escape magnet 34 in attracting its armature opens the opercircuit of secondary magnet. thus preventing overthrow of the switch it, for any reason. the side-switch wipers are not nomptly moved into their third position. v i' hen the side-switch wipers 26 and 27 are moved into their third position, the i; 1. ma -net 42 of the connector, which also performs the functions normally performed by the stepping relay, is energized. This energizing circuit extends from grounded battery, left-hand winding of primarry in net 42, side-switch wiper 43 in its first p0... on, lower side of the line, brush 39. side-switch wipers 26 and 24", finder brush 10. substation apparatus A, finder brush side-switch wiper 24*, upper side ot the line. side-switch wiper 2'? in its tnird position. selector brush 40, side-switch wiper in its first position. right-hand winding of primar magnet 42 to ground. Magnet 42 attracts its armature and thereby completes an energizing circuit for the slow operating release magnet 44-. which in this system also performs the functions normally performed by the second slow relay. The energizing circuit of magnet 44 extends irom battery, magnet 44, normally closed contact 45, conductor 46. armature and front contact oi magnet 42, side-switch wiper 47 in position 1, to ground. The magnet 44 attracts armatures and at its lef -hand armature ompletes a locking circuit for itself over the circuit previously described. hen the calling device is operated to send the tens impulses, primary magnet 42 vibrates its armatures to advance the connector switch in its primary movement. At the first retraction of the armatures of magnet 42. an energizing circuit for escape mag- O is completed from grounded battery,

- to 12:- winding ct magnet 48. conductor 49, sideswitch wiper 51 in its first position. righthand front contact and armature of magnet conductor 52, hack contact and arma- '.et 42. to ground. Magnets 44 and 48 are adiusted to release slowly when t energizing circuits are interrupted. hmvever. at the close of the tens impulses magnet 42 attracts its for a relatively long interval the energizinw circuit for escape magnet 48 is interrupted. Escape magnet 48 deenergizes and ther on moves the side-switch wipers into their second position.

When the sideswitch wipers 43 and 55 more into their second position, secondary magnet 54 has its operating circuit completed from grounded battery, middle winding of this magnet, side-switch wiper 43 in its second position, over the path previously described for the operating circuit of the primary magnet, side-switch wiper in its second position, right-hand winding of secondary magnet 54, to ground. The secondary magnet is energized and attracts its armature. In response to impulses from the sending device corresponding to the units digit of the desired number, secondary magnet 54 vibrates its armature. When the secondary magnet attracts its armature, the release magnet will then be maintained energized over a circuit which may be traced from grounded battery, release magnet 44, its armature and front contact, conductor 56, side-switch wiper 73 in its second position, armature and front contact of secondary magnet 54, conductor 55 side-switch wiper 47 in its second position, to ground. Also in this position of the side-switch wipers, escape magnet 48 has its operating circuit completed over the following path: grounded battery, escape magnet 48, conductor 49, side-switch wiper 51, right-hand armature and front contact of release magnet 44, conductor 58, armature and back contact or" secondary magnet 54, conductor 55*, side-switch wiper 47 in its second position, to ground. It will be remembered that the release magnet 44 and the escape magnet 48 are slow to release, so that they do not deenergize during the momentary interruptions of their operating circuits when the armature ot' the secondary magnet 54 is vibrated.

W hen the test brush 5'? of the connector is placed on the test terminal 59 of the desired line. ii": the desired line is idle, this condition will be indicated by raised potential at the test terminal. lin this ase the escape net 48 will be deenerglzed and will there-' upon move the sice-switch wipers into their thlrd position. It, however. the desired line is busy, a timing device 60 is provided to prevent more than one connector seizing the desired line when it becomes idle, in case several connectors should be waiting to seize the terminals of this line.

This timing device consists of a constantly rotating shaft carrying discs provided with properly positioned insulating segments. With this timing device, the escape magnet 48 has an energizing circuit extending from grounded battery, escape magnet 48. left-hand winding of secondary magnet 54; armature and front contact of escape magnet 48, side-switch wiper 61 in its second position, brush 68, a conducting portion of the constantly rotating disc 63 and its shaft, through secondary winding of induction coil 62 to ground. A busy tone is imposed on the circuit just described, by means of the primarry winding 73 of the induction coil and interrupter 72, The secondary magnet 5e actsas an induction coil and transmits the busy tone to the calling subscribers recelver.

the desired line becomes idle, the en receiver, whereupon the energizing circuit of escape magnet 48 which now extends from grounded battery, magnet L8,conductor 49, side-switch wiper 51 in its third position armature and back contact of relay 65 to ground, is interrupted at the armature of relay 65. The escape magnet upon deenergizing moves'the side-switch wipers into their fourth or talking position.

tshould be noted that the talking battery is supplied to the calling line through the secondary magnet 54. This maintains the secondary magnet energized during the conversation. The talking battery of the called subscribe/Vs line supplied through the windings of the primary magnet 42.

lhe release of the switches utilized in establishing this connection is accomplished as follows: Nhen the calling subscriber A replaces his receiver upon its switchhook, the secondary magnet 54, is deenergized. The secondary magnet 54- thereupon retracts its armature and interrupts the energizing circuit of release magnet 44 .which was previously maintained from grounded battery, magnet 414:, left-hand armature and front contact of this magnet, conductor 56, lefthand armature and front contact of magnet 42, front contact and armature of secondary magnet 54, conductor 55 side-switch wiper 47 in its fourth position to ground. The release magnet thereupon retracts its armature and withdraws its holding pawls.

The release of the preceding selectors is accomplished when escape magnet 34 is again energized. This interrupts the energizing circuit of the release magnet 28, which circuit extends om battery, low-rcsistance winding and high-resistance winding of release magnet 28, side-switch wiper 38 in its third posi-v tion, armature and back contact of escape magnet 3% to ground. Release magnet 28, in retracting its armatures, withdraws the holding pawls and permits the switch to restore to normal. Escape magnet 34: which controls this release is energized. over a circuit which extends from grounded battery, escape mag- Zing circuit escape magnet 3st, may be traced from grounded brettery, primary magnet T, escape magnet 12, side-switch wiper is in its third position, side-switch wiper in its tl'iircposition, side-switcl i wiper 35 in its third position, over the circuit previously described. The

release magnet 19 is deenergized and its armature withdraws the holding pawls'as previously described.

The release of the connector switch. is also controlled the called party. l l hen the called party replaces his receiver, the primary magnet 42 retrai-ts its ari'natures, and at its left-hand armature and front contart ii'iterrupts the operating circuit of the release magnet a l. lt will be remembered that in position '4; of side switch wiper 73, this release circuit extends from grounded battery, release magnet a l, its left-hand armature and front contact, conductor 56, lefthand armature and front contact of relay armature and front contact of relay 5%, conductor 55, side-switch wiper 4? in posh tion 4;, to ground.

lfthe calling party abandons the call, while sending impulses corresponding to the lirstdigit of the desired number, primary magnet will retract its armature and at its front contact and armature interrupts the energizing circuit of the release magnet 28, whereupon this magnet will restore the switch to its normal position. If the calling subscriber abandons the call before the impulsescorresponding to the tens digits of the desired number are sent, primary magnet 4-2 will retract its armature and thereby intorru at the ener 'izin circuit for the release,

magnet 44, which circuit is maintained from grounded battery, release magnet 4A, lefthand armature and front contact of this mag net, conductor 4C6, right-hand armature and front contact of rimar ma net 42 side i '7 switch wiper l? in its first position to ground.

If the calling subscriber abandons the call beund.

t will be understood that this disclosure is merely illustrative of applicants improved system, and that the scope of the in ention will be limited only by the appended claims.

lVhat is claimed is:

1. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for interconnecting said incoming line with any of said outgoing lines, a motor magnet for said switch, means for intermittently actuating said motor magnet, circuit-controlling switch, and an operating magnet therefor controlled by said motor magnet and arranged to be actuated at the close of a series of actuations of said motor magnet.

2. In an automatic telephone system, an automatic switch, telephone lines terminating therein in groups, a primary steppin magnet for moving said switch to select a group of said lines, a sender for intermittently actuating said primary magnet, a secondary stepping magnet for automatically moving said switch over the selected group to pick out an idle line therein, means for maintaining said secondary stepping magnet energized during the operation of said primary magnet, a circuit controlling switch having an operating magnet, and a circuit for said operating magnet controlled at a contact of said secondary stepping magnet.

3. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for connecting said incoming line with any of said outgoing lines, a motor magnet for advancing said switch connected directly to said incoming line, armature contacts controlled by said motor magnet, a slow release magnet, and a circuit for said release magnet including contacts of said motor magnet to maintain said release magnet energized while the motor magnet is operating.

4. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for connecting said incoming line with any of said outgoing lines, a motor magnet for advancing said switch connected directly to said incoming line, armature contacts controlled by said motor magnet, a release net, an escape magnet, and circuits for said release magnet controlled by said motor magnet and said escape magnet respectively.

5. In a telephone system, a switch, a primary motor magnet for said switch, armature contacts controlled by said magnet, a secondary motor magnet for said switch, a sender for intermittently operating said primary magnet, a circuit including said armature contacts for maintaining said secondary magnet energized during the operation of said primary magnet, a control switch, and a circuit for the magnet of said control switch closed by the operation of said secondary magnet,

h, a pri- 6. In'a tclenhonc s stem, a switc ng said mary motor magnet for opcrat switch, armature contacts con ll magnet, a secondary mot crating said switcl an a trolling switch, an oper I 1 auxiliary switch, circuit .101 said second n =t controlled at said contacts oi riniary magnet. and circuit for said an. iliai' switch magnet controlled 1;; said secondary magnet.

7. In a telephone system, a switch, a motor magnet for operating said switch, a slow magnet for releasing said switch, a side switch, armature contacts for said motor magnet, and a circuit for said release magnet including said armature contacts to maintain the release magnet energized in a certain position of said side switch.

8. In a telephone system, a switch, a motor magnet for operating said switch, a slow magnet for releasing said switch, a side switch, armature contacts for said motor magnet, and a circuit for said release magnet including said armature contacts to maintain the release magnet energized in a plurality ofpositions of said side switch.

9. In a telephone system, an incoming line, a plurality of outgoing lines, an automatic switch for connecting said incoming line with any of said outgoing lines, a motor magnet having windings connected directly to said incoming line for advancing said switch to the desired outgoing line, an electromagnet adopted to operate in case the called line is bus a busy tone source, and a circuit including said source and a winding of said motor magnet closed by the operation of said electromagnet, sail winding being inductively related to the windings in the incoming line. Y

10. In a telephone system, an incoming line, a plurality of outgoing lines, an automatic switch for connecting said incoming line with any of said outgoing lines, a motor magnet connected directly to said incoming line for advancing said switch to the desired outgoing line, an electromagnet adapted to operate in case the called line is busy, a busy tone source, a circuit in cluding said source and a winding of said motor magnet closed by the operation of said clectromagnet, said winding being inductively related to the windings in the in- COIHiIlg line, and means actuated by the called line becoming idle for disconnecting said tone source from the calling line and for causing said switch to signal the called line.

11. In a telephone system, an incoming line, a plurality of outgoing lines, an automatic switch for connecting said incoming line with any of said outgoin lines, a motor magnet connected directly to said incoming line for advancing said switch to the desired outgoing line, a test relay, a circuit for operating the same if the called line is busy, and including a test contact of said called line, a busy tone source, a timing device, a locking circuit including said test relay, said source, a Windin of said motor magnet, and said timing device closed upon the operation of said test relay, said Winding being inductively related to the winding in the incoming line, means actuated by the called line becoming idle for opening the energizing circuit of said. relay, and means controlled by the timing device for opening the locking circuit of said relay to disconnectsaid tone source, and means for applying ringingcurrent to the called line. 7

In Witness whereof, I hereunto subscribe my name this 13th day of January A. D, 1917.

(Jr-marine L. eoonizun. V 

